A student-leader at Chapman from 1957-61, Trumbo was a team captain on the Panthers’ baseball and basketball teams, as well as president of the Associated Student Body. In his playing days he helped Chapman basketball to four NCAA tournaments, including the Panthers' runner up team at the 1960 national championships in Evansville, Ind. He won Chapman’s Hertzog Trophy in baseball as the team's most valuable player and was named Co-Outstanding Senior Athlete in 1961.
Trumbo’s basketball coaching career included stops at Sonoma State, Idaho and Santa Rosa Junior College. He also served as Director of Athletics at Hawaii-Hilo and Cal State Monterey Bay.